Cellular senescence and hepatitis B-related hepatocellular carcinoma: An intriguing link

A review of Phyllanthus urinaria L. in the treatment of liver disease: viral hepatitis, liver fibrosis/cirrhosis and hepatocellular carcinoma

Due to the pathological production of liver disease in utility particularly complexity, the morbidity and mortality of liver disease including viral hepatitis, liver fibrosis/cirrhosis and hepatocellular carcinoma (HCC) are rapidly increasing worldwide. Considering its insidious onset, rapid progression and drug resistance, finding an effective therapy is particularly worthwhile. Phyllanthus urinaria L. (P. urinaria), an ethnic medicine, can be applied at the stages of viral hepatitis, liver fibrosis/cirrhosis and HCC, which demonstrates great potential in the treatment of liver disease. Currently, there are numerous reports on the application of P. urinaria in treating liver diseases, but a detailed analysis of its metabolites and a complete summary of its pharmacological mechanism are still scarce. In this review, the phytochemical metabolites and ethnopharmacological applications of P. urinaria are summarized. Briefly, P. urinaria mainly contains flavonoids, lignans, tannins, phenolic acids, terpenoids and other metabolites. The mechanisms of P. urinaria are mainly reflected in reducing surface antigen secretion and interfering with DNA polymerase synthesis for anti-viral hepatitis activity, reducing hepatic stellate cells activity, inflammation and oxidative stress for anti-liver fibrosis/cirrhosis activity, as well as preventing tumor proliferation, invasion and angiogenesis for anti-HCC activity via relevant signaling pathways. Accordingly, this review provides insights into the future application of natural products in the trilogy of liver diseases and will provide a scientific basis for further research and rational utilization of P. urinaria.

Insights into the Correlation between Toll-Like Receptor 2 Polymorphism and HBV-Related Disease Progression and Occurrence of Hepatocellular Carcinoma: A Case-Control Study in Egyptian Patients

Methods

In total, 170 chronic HBV patients and 50 healthy controls of comparable age and gender were included in this case-control study. Clinical, laboratory, and imaging evaluations were conducted. ELISA was used to determine serum IL-6 levels, and TLR2 (rs3804099) genotyping allelic discrimination assay was performed using real-time PCR.

Results

IL-6 values were significantly higher in the HCC group, followed by the cirrhotic group, than those in chronic hepatitis and control groups (p < 0.001), with a significant correlation with disease activity and progression parameters. TRL2 homozygous TT was the most frequent in the control group, but the CC genotype was significantly more prevalent in the HCC group than that in the other groups. Furthermore, the CC genetic variant was associated with higher levels of IL-6 and viral load in all HBV patients, whereas the TT genotype was associated with larger tumor size. Multivariate regression analysis demonstrated that in chronic HBV patients, viral load and TRL2 polymorphism are independent risk factors associated with the progression from chronic hepatitis to liver cirrhosis and to HCC. Similarly, the HBV viral load (p=0.03, OR = 2.45, and 95% CI: 1.69-3.65), IL-6 levels (p=0.04, OR = 3.45, and 95% CI: 2.01-6.9), and TRL2 variants (p=0.01, OR = 4.25, and 95% CI: 2.14-13.5) are independent risk factors associated with disease progression from cirrhosis to HCC.

Conclusion

In chronic HBV patients, TRL2 polymorphism and higher IL-6 levels were positively correlated with a higher likelihood of HCC and chronic hepatitis B disease activity and progression.

Cell senescence in liver diseases: pathological mechanism and theranostic opportunity

The liver is not oblivious to the passage of time, as ageing is a major risk factor for the development of acute and chronic liver diseases. Ageing produces alterations in all hepatic cells, affecting their phenotype and function and worsening the prognosis of liver disease. The ageing process also implies the accumulation of a cellular state characterized by a persistent proliferation arrest and a specific secretory phenotype named cellular senescence. Indeed, senescent cells have key roles in many physiological processes; however, their accumulation owing to ageing or pathological conditions contributes to the damage occurring in chronic diseases. The aim of this Review is to provide an updated description of the pathophysiological events in which hepatic senescent cells are involved and their role in liver disease progression. Finally, we discuss novel geroscience therapies that could be applied to prevent or improve liver diseases and age-mediated hepatic deregulations.

Old age as a risk factor for liver diseases: Modern therapeutic approaches

Recent scientific interest has been directed towards age-related diseases, driven by the significant increase in global life expectancy and the growing population of individuals aged 65 and above. The ageing process encompasses various biological, physiological, environmental, psychological, behavioural, and social changes, leading to an augmented susceptibility to chronic illnesses. Cardiovascular, neurological, musculoskeletal, liver and oncological diseases are prevalent in the elderly. Moreover, ageing individuals demonstrate reduced regenerative capacity and decreased tolerance towards therapeutic interventions, including organ transplantation. Liver diseases, such as non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis, fibrosis, and cirrhosis, have emerged as significant public health concerns. Paradoxically, these conditions remain underestimated despite their substantial global impact. Age-related factors are closely associated with the severity and unfavorable prognosis of various liver diseases, warranting further investigation to enhance clinical management and develop novel therapeutic strategies. This comprehensive review focuses specifically on age-related liver diseases, their treatment strategies, and contemporary practices. It provides a detailed account of the global burden, types, molecular mechanisms, and epigenetic alterations underlying these liver pathologies.

Contribution of viral and bacterial infections to senescence and immunosenescence

Cellular senescence is a key biological process characterized by irreversible cell cycle arrest. The accumulation of senescent cells creates a pro-inflammatory environment that can negatively affect tissue functions and may promote the development of aging-related diseases. Typical biomarkers related to senescence include senescence-associated β-galactosidase activity, histone H2A.X phosphorylation at serine139 (γH2A.X), and senescence-associated heterochromatin foci (SAHF) with heterochromatin protein 1γ (HP-1γ protein) Moreover, immune cells undergoing senescence, which is known as immunosenescence, can affect innate and adaptative immune functions and may elicit detrimental effects over the host's susceptibility to infectious diseases. Although associations between senescence and pathogens have been reported, clear links between both, and the related molecular mechanisms involved remain to be determined. Furthermore, it remains to be determined whether infections effectively induce senescence, the impact of senescence and immunosenescence over infections, or if both events coincidently share common molecular markers, such as γH2A.X and p53. Here, we review and discuss the most recent reports that describe cellular hallmarks and biomarkers related to senescence in immune and non-immune cells in the context of infections, seeking to better understand their relationships. Related literature was searched in Pubmed and Google Scholar databases with search terms related to the sections and subsections of this review.

Hepatocellular carcinoma: The virus or the liver?

Hepatocellular carcinoma (HCC) represents a major public health problem being one of the most common causes of cancer-related deaths worldwide. Hepatitis B (HBV) and C viruses have been classified as oncoviruses and are responsible for the majority of HCC cases, while the role of hepatitis D virus (HDV) in liver carcinogenesis has not been elucidated. HDV/HBV coinfection is related to more severe liver damage than HBV mono-infection and recent studies suggest that HDV/HBV patients are at increased risk of developing HCC compared to HBV mono-infected patients. HBV is known to promote hepatocarcinogenesis via DNA integration into host DNA, disruption of molecular pathways by regulatory HBV x (HBx) protein and excessive oxidative stress. Recently, several molecular mechanisms have been proposed to clarify the pathogenesis of HDV-related HCC including activation of signalling pathways by specific HDV antigens, epigenetic dysregulation and altered gene expression. Alongside, ongoing chronic inflammation and impaired immune responses have also been suggested to facilitate carcinogenesis. Finally, cellular senescence seems to play an important role in chronic viral infection and inflammation leading to hepatocarcinogenesis. In this review, we summarize the current literature on the impact of HDV in HCC development and discuss the potential interplay between HBV, HDV and neighbouring liver tissue in liver carcinogenesis.

HCV spontaneous clearers showed low senescence profile in people living with HIV under long ART

Coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) increases immune activation, inflammation, and oxidative stress that could lead to premature senescence. Different HCV infections, either acute or chronic infection, could lead to distinct premature cellular senescence in people living with HIV (PLWHIV). Observational study in 116 PLWHIV under antiretroviral treatment with different HCV status: (i) n = 45 chronically infected with HCV (CHC); (ii) n = 36 individuals who spontaneously clarify HCV (SC); (iii) n = 35 HIV controls. Oxidative stress biomarkers were analyzed at lipid, DNA, protein, and nitrates levels, as well as antioxidant capacity and glutathione reductase enzyme. Replicative senescence was evaluated by relative telomere length (RTL) measurement. Additionally, 26 markers of Senescence-Associated Secretory Phenotype (SASP) were analyzed by multiplex immunoassays (Luminex xMAP technology). Differences were evaluated by generalized linear model (GLMs) adjusted by most significant covariates. The SC group had a senescence signature similar to the HIV control group and slightly lower SASP levels. However, significant differences were observed with respect to the CHC group, where an increase in the nitrate concentration [adjusted arithmetic mean ratio, aAMR = 1.73 (1.27-2.35), p < 0.001, q = 0.009] and the secretion of 13 SASP-associated factors [granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-β, interleukin (IL)-1β, IL-2, IL-8, IL-13, tumor necrosis factor (TNF)-α, IL-1α, IL-1RA, IL-7, IL-15, C-X-C motif chemokine ligand 10 (IP-10), stem cell factor (SCF); q < 0.1)] was detected. The CHC group also showed higher values of IL-1α, IP-10, and placental growth factor 1 (PIGF-1) than HIV controls. The SC group showed a slightly lower senescence profile than the HIV group, which could indicate a more efficient control of viral-induced senescence due to their immune strengths. Chronic HCV infection in PLWHIV led to an increase in nitrate and elevated SASP biomarkers favoring the establishment of viral persistence.

A novel anti-HBV agent, E-CFCP, restores Hepatitis B virus (HBV)-induced senescence-associated cellular marker perturbation in human hepatocytes

Cellular senescence is a cellular state with a broad spectrum of age-related physiological conditions that can be affected by various infectious diseases and treatments. Therapy of hepatitis B virus (HBV) infection with nucleos(t)ide analogs [NA(s)] is well established and benefits many HBV-infected patients, but requires long-term, perhaps lifelong, medication. In addition to the effects of HBV infection, the effects of NA administration on hepatocellular senescence are still unclear. This study investigated how HBV infection and NA treatment influence cellular senescence in human hepatocytes and humanized-liver chimeric mice chronically infected with live HBV. HBV infection upregulates or downregulates multiple cellular markers including senescence-associated β-galactosidase (SA-β-Gal) activity and cell cycle regulatory proteins (e.g., p21^CIP1) expression level in hepatocellular nuclei and humanized-mice liver. A novel highly potent anti-HBV NA, E-CFCP, per se did not have significant disturbance on markers evaluated. Besides, E-CFCP treatment restored HBV-infected cells to their physiological phenotypes that are comparable to the HBV-uninfected cells. The results reported here demonstrate that, regardless of the mechanism(s), chronic HBV infection perturbates multiple senescence-associated markers in human hepatocytes and humanized-mice liver, but E-CFCP can restore this phenomenon.

Emerging role of aging in the progression of NAFLD to HCC

With the aging of global population, the incidence of nonalcoholic fatty liver disease (NAFLD) has surged in recent decades. NAFLD is a multifactorial disease that follows a progressive course, ranging from simple fatty liver, nonalcoholic steatohepatitis (NASH) to liver cirrhosis and hepatocellular carcinoma (HCC). It is well established that aging induces pathological changes in liver and potentiates the occurrence and progression of NAFLD, HCC and other age-related liver diseases. Studies of senescent cells also indicate a pivotal engagement in the development of NAFLD via diverse mechanisms. Moreover, nicotinamide adenine dinucleotide (NAD⁺), silence information regulator protein family (sirtuins), and mechanistic target of rapamycin (mTOR) are three vital and broadly studied targets involved in aging process and NAFLD. Nevertheless, the crucial role of these aging-associated factors in aging-related NAFLD remains underestimated. Here, we reviewed the current research on the roles of aging, cellular senescence and three aging-related factors in the evolution of NAFLD to HCC, aiming at inspiring promising therapeutic targets for aging-related NAFLD and its progression.

The cGAS/STING signaling pathway: a cross-talk of infection, senescence and tumors

The cGAS/STING signaling pathway is an important part of the cytoplasmic DNA sensor, which can trigger a type I interferon response to microbial infection when pathogenic DNA is detected. However, continuous inhibition of cGAS/STING signaling by viral infection may be an important cause of tumorigenesis. At the same time, recent studies have shown that although the cGAS/STING signaling pathway also plays a core role in anti-tumor immunity and cell senescence, the inflammatory response induced by cGAS/STING signaling will also promote tumorigenesis in different backgrounds. Here, we discuss the role of cGAS/STING in the context of infection, senescence, and tumors, especially with respect to progression, to facilitate a better understanding of the mechanism of the cGAS/STING pathway.

Cellular Senescence in Hepatocellular Carcinoma: The Passenger or the Driver?

With the high morbidity and mortality, hepatocellular carcinoma (HCC) represents a major yet growing burden for our global community. The relapse-prone nature and drug resistance of HCC are regarded as the consequence of varying intracellular processes and extracellular interplay, which actively participate in tumor microenvironment remodeling. Amongst them, cellular senescence is regarded as a fail-safe program, leading to double-sword effects of both cell growth inhibition and tissue repair promotion. Particularly, cellular senescence serves a pivotal role in the progression of chronic inflammatory liver diseases, ultimately leading to carcinogenesis. Given the current challenges in improving the clinical management and outcome of HCC, senescence may exert striking potential in affecting anti-cancer strategies. In recent years, an increasing number of studies have emerged to investigate senescence-associated hepatocarcinogenesis and its derived therapies. In this review, we intend to provide an up-to-date understanding of liver cell senescence and its impacts on treatment modalities of HCC.

Aging of Liver in Its Different Diseases

The proportion of elderly people in the world population is constantly increasing. With age, the risk of numerous chronic diseases and their complications also rises. Research on the subject of cellular senescence date back to the middle of the last century, and today we know that senescent cells have different morphology, metabolism, phenotypes and many other characteristics. Their main feature is the development of senescence-associated secretory phenotype (SASP), whose pro-inflammatory components affect tissues and organs, and increases the possibility of age-related diseases. The liver is the main metabolic organ of our body, and the results of previous research indicate that its regenerative capacity is greater and that it ages more slowly compared to other organs. With age, liver cells change under the influence of various stressors and the risk of developing chronic liver diseases such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), alcoholic steatohepatitis (ASH) and hepatocellular carcinoma (HCC) increases. It has been proven that these diseases progress faster in the elderly population and in some cases lead to end-stage liver disease that requires transplantation. The treatment of elderly people with chronic liver diseases is a challenge and requires an individual approach as well as new research that will reveal other safe and effective therapeutic modalities.

Identification of cell senescence molecular subtypes in prediction of the prognosis and immunotherapy of hepatitis B virus-related hepatocellular carcinoma

Hepatitis B virus (HBV)-infected hepatocellular carcinoma (HCC) has a high incidence and fatality rate worldwide, being among the most prevalent cancers. The growing body of data indicating cellular senescence (CS) to be a critical factor in hepatocarcinogenesis. The predictive value of CS in HBV-related HCC and its role in the immune microenvironment are unknown. To determine the cellular senescence profile of HBV-related HCC and its role in shaping the immune microenvironment, this study employed a rigorous evaluation of multiple datasets encompassing 793 HBV-related HCC samples. Two novel distinct CS subtypes were first identified by nonnegative matrix factorization, and we found that the senescence-activated subgroup had the worst prognosis and correlated with cancer progression. C1 and C2 were identified as the senescence-suppressed and senescence-activated subgroups. The immune microenvironment indicated that C2 exhibited a relatively low immune status, higher tumor purity, and lower immune scores and estimated scores, while the C1 subgroup possessed a better prognosis. The CS score signature based on five genes (CENPA, EZH2, G6PD, HDAC1, and PRPF19) was established using univariate Cox regression and the lasso method. ICGC-LIRI and GSE14520 cohorts were used to validate the reliability of the CS scoring system. In addition, we examined the association between the risk score and hallmark pathways through gene set variation analysis and gene set enrichment analysis. The results revealed a high CS score to be associated with the activation of cell senescence-related pathways. The CS score and other clinical features were combined to generate a CS dynamic nomogram with a better predictive capacity for OS at 1, 2, and 3 years than other clinical parameters. Our study demonstrated that cellular senescence patterns play a non-negligible role in shaping the characteristics of the immune microenvironment and profoundly affecting tumor prognosis. The results of this study will help predict patient prognosis more accurately and may assist in development of personalized immunotherapy for HBV-related HCC patients.

Development and validation of a novel cellular senescence-related prognostic signature for predicting the survival and immune landscape in hepatocellular carcinoma

Background: Cellular senescence is a typical irreversible form of life stagnation, and recent studies have suggested that long non-coding ribonucleic acids (lncRNA) regulate the occurrence and development of various tumors. In the present study, we attempted to construct a novel signature for predicting the survival of patients with hepatocellular carcinoma (HCC) and the associated immune landscape based on senescence-related (sr) lncRNAs.

Method: Expression profiles of srlncRNAs in 424 patients with HCC were retrieved from The Cancer Genome Atlas database. Lasso and Cox regression analyses were performed to identify differentially expressed lncRNAs related to senescence. The prediction efficiency of the signature was checked using a receiver operating characteristic (ROC) curve, Kaplan–Meier analysis, Cox regression analyses, nomogram, and calibration. The risk groups of the gene set enrichment analysis, immune analysis, and prediction of the half-maximal inhibitory concentration (IC50) were also analyzed. Quantitative real-time polymerase chain reaction (qPCR) was used to confirm the levels of AC026412.3, AL451069.3, and AL031985.3 in normal hepatic and HCC cell lines.

Results: We identified 3 srlncRNAs (AC026412.3, AL451069.3, and AL031985.3) and constructed a new risk model. The results of the ROC curve and Kaplan–Meier analysis suggested that it was concordant with the prediction. Furthermore, a nomogram model was constructed to accurately predict patient prognosis. The risk score also correlated with immune cell infiltration status, immune checkpoint expression, and chemosensitivity. The results of qPCR revealed that AC026412.3 and AL451069.3 were significantly upregulated in hepatoma cell lines.

Conclusion: The novel srlncRNA (AC026412.3, AL451069.3, and AL031985.3) signatures may provide insights into new therapies and prognosis predictions for patients with HCC.

TLR2, as a Pathogen Recognition Receptor, Plays Critical Roles in Hepatitis B Outcome

The immune system of active and inactive chronic hepatitis B, as prolonged forms of hepatitis B, is unable to eradicate hepatitis B virus (HBV) from the infected hepatocytes completely. Toll-like receptors (TLRs) play key roles in the viral recognition and promotion of appropriate immune responses. The molecules also participate in the alteration of the target cell functions and transformation. TLR2 is the unique molecule that makes either homodimer or heterodimer with TLR1 and 6 and shows variable roles against viral infections. Therefore, it has been hypothesized that TLR2 may participate in both immune response against HBV and induction of the virus-related hepatic complications. The studies confirm the hypothesis and revealed that TLR2 is not only one of the main molecules altering the course of HBV infection, but also plays key roles in induction of hepatocellular carcinoma (HCC) and liver cirrhosis. However, recent studies demonstrated that the molecule can fight against HCC and liver cirrhosis. Collectively, it appears that nutrition habits, TLR2 gene polymorphisms, gut microbiome, HBV antigens, and activation of other receptors may play key roles in the determination of TLR2 functions.

Mulberry fruit polysaccharides alleviate diethylnitrosamine/phenobarbital-induced hepatocarcinogenesis in vivo: the roles of cell apoptosis and inflammation

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, and chemoprevention represents a feasible treatment to reduce the mortality of this carcinoma. Mulberry fruit polysaccharides (MFP) possess immunoregulatory and anti-inflammatory effects, which have been reported to alleviate liver damage evoked by CCl4 or alcohol in previous reports. However, its chemopreventive effect against liver carcinogenesis is insufficient. The present study was aimed to investigate the possible role of MFP as a pro-apoptosis, and anti-inflammatory agent to possess its chemoprevention property. Hepatocarcinogenesis was induced by diethylnitrosamine/phenobarbital (DEN/PB) for 14 weeks. The DEN/PB-administered rats were co-treated with different doses of MFP (50 or 100 mg/kg body weight) by oral gavage for 14 weeks. Basic hepatic function indexes (AST, ALT, ALP, GGT, total bilirubin, and albumin), and hepatic tumor biomarkers (AFP, CEA, and CA19.9), together with histological assessment were performed. Besides, the hepatic apoptosis markers (Bcl-2, Bax, caspase3, and caspase9), inflammation markers (IL-1β, TNF-α, and NF-κB), and mutT homologue gene 1 (MTH1) were examined. Oral gavage of MFP inhibited the elevations of hepatic function indexes and hepatic tumor biomarkers and alleviated pathological changes in hepatic tissue. In addition, the hepatic apoptosis markers, inflammation markers, and the mRNA level of MTH1 were abnormal in DEN/PB group, which were reversed by MFP treatment. In conclusion, MFP is an effective agent that provides chemoprevention against DEN/PB-evoked hepatocarcinogenesis via inhibition of inflammation and induction of apoptosis.

Exploring the Mechanisms of Arsenic Trioxide (Pishuang) in Hepatocellular Carcinoma Based on Network Pharmacology

OBJECTIVE

Arsenic trioxide (Pishuang, Pishi, arsenolite, As2O3, and CAS 1327-53-3), a naturally occurring and toxic mineral as a drug for more than 2000 years in China, has been found to have a valuable function in hepatocellular carcinoma (HCC) in recent years. However, its exact mechanism remains to be elucidated. Therefore, this study was intended to explore the potential anti-HCC mechanism of arsenic trioxide through network pharmacology.

METHODS

The potential targets of arsenic trioxide were collected from PubChem and TargetNet. HCC targets were obtained from the GeneCards database. Then, a protein-protein interaction (PPI) network of arsenic trioxide and HCC common targets was established using STRING. GO and KEGG pathway enrichment analyses were performed by the Database for Annotation, Visualization, and Integrated Discovery (DAVID). Finally, an arsenic trioxide-target-pathway-HCC network was built by Cytoscape 3.2.1, and network topological analysis was carried out to screen the key candidate targets.

RESULTS

A total of 346 corresponding targets of arsenic trioxide and 521 HCC-related targets were collected. After target mapping, a total of 52 common targets were obtained. GO analysis showed that the biological process was mainly involved in the negative regulation of cellular senescence, response to tumor necrosis factor, and cellular response to hypoxia. Molecular functions included NF-kappa B binding, enzyme binding, p53 binding, and transcription factor binding. Cellular components mainly were replication fork, ESC/E(Z) complex, RNA polymerase II transcription factor complex, and organelle membrane. KEGG pathways were mainly enriched in the PI3K-Akt signaling pathway, VEGF signaling pathway, p53 signaling pathway, HIF-1 signaling pathway, TNF signaling pathway, AMPK signaling pathway, NF-kappa B signaling pathway, FoxO signaling pathway, ErbB signaling pathway, and MAPK signaling pathway. In the arsenic trioxide-target-pathway-HCC network, targets such as AKT1, RAF1, RELA, TP53, and PTEN had a higher degree. Conclusions. Our study showed that key targets of arsenic trioxide were mainly involved in multiple biological processes and pathways. It provided a theoretical basis for the screening of drug targets.

Cellular senescence in liver fibrosis: Implications for age-related chronic liver diseases

INTRODUCTION

New insights indicate a causative link between cellular senescence and liver fibrosis. Senescent hepatic stellate cells (HSCs) facilitate fibrosis resolution, while senescence in hepatocytes and cholangiocytes acts as a potent mechanism driving liver fibrogenesis. In many clinical studies, telomeres and mitochondrial DNA contents, which are both aging biomarkers, were reportedly associated with a degree of liver fibrosis in patients with chronic liver diseases (CLDs); this highlights their potential as biomarkers for liver fibrogenesis. A deeper understanding of mechanisms underlying multi-step progression of senescence may yield new therapeutic strategies for age-related chronic liver pathologies.

AREAS COVERED

This review examines the recent findings from preclinical and clinical studies on mechanisms of senescence in liver fibrogenesis and its involvement in liver fibrosis. A comprehensive literature search in electronic databases consisting of PubMed and Scopus from inception to 31 August 2021 was performed.

EXPERT OPINION

Cellular senescence has diagnostic, prognostic, and therapeutic potential in progressive liver complications, especially liver fibrosis. Stimulating or reinforcing the immune response against senescent cells may be a promising and forthright biotherapeutic strategy. This approach will need a deeper understanding of the immune system's ability to eliminate senescent cells and the molecular and cellular mechanisms underlying this process.

Senescence in HBV-, HCV- and NAFLD- Mediated Hepatocellular Carcinoma and Senotherapeutics: Current Evidence and Future Perspective

Cell senescence constitutes a physiological process that serves as protection from malignant transformation of cells. However, recent scientific discoveries also identify cell senescence as pivotal in hepatocellular cancer (HCC) biology. The review herein aimed to accumulate evidence on senescence as a mediator of HCC occurrence in hepatitis B (HBV), C (HCV) virus infections, and non-alcoholic fatty liver disease (NAFLD). In HBV infection, the carcinogenic HBV X protein frequently mutates during chronic infection, and subsequently exhibits different effects on senescence. In HCV infection, senescent non-functional T-cells do not effectively clear pre-malignant hepatocytes. Furthermore, the HCV Core protein inhibits the occurrence of normal stress-induced hepatocyte senescence, allowing damaged cells to maintain their proliferative potential. In NAFLD-mediated HCC, current data point towards the gut microbiome and hepatic stellate cell senescence. Additionally, senescence contributes in the development of resistance in targeted therapies, such as sorafenib. Finally, the promising role of senotherapeutics in HCC was also explored. Overall, although we may still be at a primitive stage in fully unraveling the role of senescence in cancer, it seems that understanding and harnessing senescence may have the potential to revolutionize the way we treat hepatocellular cancer.

The role of mitochondria dysfunction and hepatic senescence in NAFLD development and progression

Senescence is a crucial player in several metabolic disorders and chronic inflammatory diseases. Recent data prove the involvement of hepatocyte senescence in the development of NAFLD (non-alcoholic fatty liver disease). As the main energy and ROS (reactive oxygen species) producing organelle, mitochondria play the central role in accelerated senescence and diseases development. In this review, we focus on the role of regulation of mitochondrial Ca²⁺ homeostasis, NAD+/NADH ratio, UPR^mt (mitochondrial unfolded protein response), phospholipids and fatty acid oxidation in hepatic senescence, lifespan and NAFLD disease susceptibility. Additionally, the involvement of mitochondrial and nuclear mutations in lifespan-modulation and NAFLD development is discussed. While nuclear and mitochondria DNA mutations and SNPs (single nucleotide polymorphisms) can be used as effective diagnostic markers and targets for treatments, advanced age should be considered as an independent risk factor for NAFLD development.

Calcium signaling in hepatitis B virus infection and its potential as a therapeutic target

As a ubiquitous second messenger, calcium (Ca2+) can interact with numerous cellular proteins to regulate multiple physiological processes and participate in a variety of diseases, including hepatitis B virus (HBV) infection, which is a major cause of hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. In recent years, several studies have demonstrated that depends on the distinct Ca2+ channels on the plasma membrane, endoplasmic reticulum, as well as mitochondria, HBV can elevate cytosolic Ca2+ levels. Moreover, within HBV-infected cells, the activation of intracellular Ca2+ signaling contributes to viral replication via multiple molecular mechanisms. Besides, the available evidence indicates that targeting Ca2+ signaling by suitable pharmaceuticals is a potent approach for the treatment of HBV infection. In the present review, we summarized the molecular mechanisms related to the elevation of Ca2+ signaling induced by HBV to modulate viral propagation and the recent advances in Ca2+ signaling as a potential therapeutic target for HBV infection. Video Abstract.

Clinical, Pathological and Genetic Characteristics of Pediatric Hepatocellular Carcinoma Associated with Hepatitis B Virus Infection

Introduction

Hepatocellular carcinoma (HCC) remains the major challenge in the management of patients with hepatitis B virus (HBV) infection. To date, limited studies have been done on pediatric HBV-associated HCC specifically.

Methods

Pediatric patients younger than 16 years with HBV-associated HCC were included in the study. HBV integration detection was performed using a high-throughput viral integration detection (HIVID) method.

Results

Among the 13 included pediatric patients, boys predominated (10, 76.9%). The median age at diagnosis of HCC was 13 years and the youngest age was 6 years. Nine patients had initially seronegative hepatitis B e antigen (HBeAg) and 4 had seropositive HBeAg. All patients had cirrhosis and elevated alpha-fetoprotein. Splenomegaly was present in all patients. Intrahepatic HBsAg was not detected in any tumor tissues from 5 patients who underwent biopsy or excision, while it was positive in all matched non-tumor tissues. In the tumor and matched non-tumor tissues from 3 individuals, HBV integration was identified except in the neoplastic specimen from 1 patient. Integration into the reported genes associated with hepatocarcinogenesis was not found in the tumor tissues from the 3 patients.

Discussion

Hypervigilance for HCC development is required in HBeAg-negative cirrhotic children. The findings based on the immunohistochemical and genetic results expand the knowledge of pediatric HCC development.